Function ExecStorePinnedBufferHeapTuple

src/backend/executor/execTuples.c:1434–1454

* Like ExecStoreBufferHeapTuple, but transfer an existing pin from the caller * to the slot, i.e. the caller doesn't need to, and may not, release the pin. */

 * to the slot, i.e. the caller doesn't need to, and may not, release the pin.
 */
TupleTableSlot *
ExecStorePinnedBufferHeapTuple(HeapTuple tuple,
							   TupleTableSlot *slot,
							   Buffer buffer)
{
	/*
	 * sanity checks
	 */
	Assert(tuple != NULL);
	Assert(slot != NULL);
	Assert(slot->tts_tupleDescriptor != NULL);
	Assert(BufferIsValid(buffer));

	if (unlikely(!TTS_IS_BUFFERTUPLE(slot)))
		elog(ERROR, "trying to store an on-disk heap tuple into wrong type of slot");
	tts_buffer_heap_store_tuple(slot, tuple, buffer, true);

	slot->tts_tableOid = tuple->t_tableOid;

	return slot;
}

/*
 * Store a minimal tuple into TTSOpsMinimalTuple type slot.